The present invention relates in general to a system for recognizing a three-dimensional body and, in more particular, to a stereoscopic vision system for processing images of which a three-dimensional object was two-dimensionally reflected, thereby to obtain the distance information of the object.
Recently, it is one of the important themes of technological development to recognize (scene analyze) a three-dimensional object on the basis of the two-dimensional image processing technique. For example, a binocular stereoscopic-vision unit to be built in an intelligent robot, which can move or run among obstacles so as not to collide with the obstacles, extracts distance information (distance image) necessary to sense and recognize the three-dimensional obstacles. The use of this distance information enables the size and position of an object to be determined and also enables a particular object to be extracted from several apparently overlapping objects on the two-dimensional image, or it enables the background, which is unnecessary for the object information on the two-dimensional image to be erased.
A stereoscopic vision system is an apparatus which (1) receives images of an object photographed from a plurality of different points of view; (2) performs the corresponding point detection with respect to whether or not the corresponding portion, which is the same portion on the actual object, exists among those images and, if it exists, finds out which portion it is; and (3) measures the actual distance between the stereoscopic vision system itself and the object in accordance with the principles of a triangulation method on the basis of the relative relation among the above-mentioned corresponding points thus discovered and the above-mentioned points of view. This system has two video cameras corresponding to the eyes of a man. A computer system is provided to perform the corresponding point detection in the images from the cameras. However, according to conventional stereoscopic vision systems, the comparison processes must be respectively performed among a number of arbitrary pixels of both images to discover the corresponding points between the two images. Therefore, the number of calculation processes, which the computer system for the stereoscopic vision system must execute, becomes enormous and takes a long time until the corresponding points are discovered. In the worst case, the suitable corresponding points cannot be correctly discovered. Consequently, a large computer system is needed, but this causes the hardware constitution of the stereoscopic vision system to be adversely complicated and reduces the practicality of the system.